18219231 has 12 divisors (see below), whose sum is σ = 26399152. Its totient is φ = 12108096.

The previous prime is 18219203. The next prime is 18219251. The reversal of 18219231 is 13291281.

It is a de Polignac number, because none of the positive numbers 2^k-18219231 is a prime.

It is a super-2 number, since 2×18219231² = 663880756462722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18219195 and 18219204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18219251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30 + ... + 6036.

Almost surely, 2^18219231 is an apocalyptic number.

18219231 is a deficient number, since it is larger than the sum of its proper divisors (8179921).

18219231 is a wasteful number, since it uses less digits than its factorization.

18219231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6350 (or 6347 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 18219231 is about 4268.3991144222. The cubic root of 18219231 is about 263.1338261700.

The spelling of 18219231 in words is "eighteen million, two hundred nineteen thousand, two hundred thirty-one".